Industrial roll

ABSTRACT

An industrial roll having inner and outer cylindrical shells held in spaced concentric relationship by one or more intermediate resilient spacer elements. The spacer elements are disposed at an angle relative to a line perpendicular to the rotational axis of the roll, and provide the sole radial support for the outer shell. Axial movement as well as axial expansion and/or contraction of one shell relative to the other may if desired be opposed by spring retainers.

United States Patent [72] Inven Fr z Peter 2.326.044 8/1943 Littleton l65/89 x l ll z rlan 2,576,036 11/1951 Ostertag etal.... 165/89 21 Appl. NO. 772,348 2.870.546 1/1959 Nelson etal. 34/124 lin d 3 1 368 3.425.488 2/1969 .larreby 165/90 atente 1 [73] Assignee Rodney Hunt Company FOREIGN PATENTS OmnseMass. 1,2l 1.918 l0/l959 France l65/83 Primary Examiner-Martin P. Schwadron Assistant Examiner-Theophil W. Streule 1 INDUSTRIAL ROLL AtI0rneyChittick. Pfund. Birch, Samuels & Gauthier 6 Claims, 7 Drawing Figs.

52 0.8. l ..1 Int 8 gflgg ABSTRACT: An lndustnal roll having mner and outer cyl1n- [so] i 165/89 83 drical shells held in spaced concentric relationship by one or l/l24 more intermediate resilient spacer elements. The spacer ele.

' ments are disposed at an angle relative to a line perpendicular 5 References Cited to the rotational axis of the roll, and provide the sole radial UNITED STATES PATENTS support for the outer shell. Axial movement as well as axial ex- 3,080.l50 3/l963 Gross pansion and/or contraction of one shell relative to the other 3.2l8.799 11/1965 Lovingham mayifdesi'ed beppsedbyspringre'ainers' 40 l 36 1\\ 1 1 11 1 3e .13 i 1\ 1 \i A 1 1 1S as I0 1 1 11 11 1 11 l 1 1 1 /e 11 1 1 1 6111 I 1 l1 1 1 5 1 11: 1M 1 \\1\ l\\ 1 34@ i 1 1 1 1 1 1 1 1 1 1 1 1 .1 38 /4\ 36 36 l \H- \\\/Q\\\ \11 H1 1 58 4o 40 INDUSTRIAL ROLL BACKGROUND OF THE INVENTION This invention relates generally to industrial rolls, and more particularly to an improved construction for rolls having inner and outer spaced concentric cylindrical walls or shells. Such rolls may be employed to either heat or cool the material being processed by circulating a heat transfer medium through the annular space formed between the inner and outer shells. Under these conditions, temperature difi'erentials normally develop between the inner and outer shells. Such temperature differentials produce thermal stresses in the various roll components, particularly the outer shell. In the prior art roll constructions, these stresses sometimes exceed the elastic limit of the shell material. When this occurs, the resulting permanent shell deformation often renders the roll unserviceable.

A primary object of the present invention is to avoid this problem by providing means for yieldably accommodating thermal expansion and/or contraction of the roll components.

To this end, either the inner or outer shell is provided with resilient relatively thin-gauged spacer elements disposed angularly in relation to a line perpendicular to the rotational axis of the roll. The outer shell surrounds the inner shell and is radially supported solely by the spacer elements, the latter preferably having helical configurations which cooperate with the inner and outer shells to define spiral passageways through which the heat transfer medium is circulated during operation of the roll. Axial movement of one shell relative to the other is opposed by spring retainer means. This construction makes possible the following advantages: radial expansion and/or contraction of one shell relative to the other due to temperature differentials experienced during operation of the roll is fully compensated for by angular deflection of the resilient inclined spacer elements. Axial expansion and/or contraction of one shell relative to the other is similarly compensated for by the spring retainer means. The development of thermal stresses in the roll components, particularly the outer shell, is therefore greatly minimized with the result that permanent deformation is effectively avoided.

This is to be contrasted to prior art heat transfer rolls wherein radially extending rigid spacer elements and/or end plates are employed to secure the outer shell relative to the inner shell. Such rigidly interconnected roll assemblies do not incorporate means for accommodating varying degrees of thermal expansioh and/or contraction, and the resulting thermal stresses frequently exceed the elastic limits of roll materials.

Other objects of the present invention as applied to heat transfer rolls include the provision of an improved seal construction between the inner and outer shells of the roll assembly. The primary advantages of this new seal construction include simplicity of design and the ability to inspect critical seal components during assembly.

Rolls constructed in accordance with the present invention may also be advantageously employed where considerations other than compensation for differential thermal expansion are of prime importance. For example, certain industrial applications require a substantially uniform nip pressure across the width of a mating set of rolls. Similarly, other applications require some means for compensating for the deflection of a rolls working surface. As will hereinafter be described in greater detail, these objectives may be accomplished with the present invention by selectively varying the ability of the inclinedresilient spacer elements to withstand angular deflection.

These and other objects and advantages of the present invention will become more apparent as the description proceeds with the aid of the accompanying drawings wherein;

FIG. 1 "is a longitudinal sectional view taken through a preferred form of a heat transfer roll embodying the concepts of the present invention;

FIG. 2 is an enlarged sectional view of one end of the roll shown in FIG. 1;

FIG. 3 is a greatly enlarged sectional view showing details of the spring retainer means and sealing arrangement shown in FIGS. 1 and 2;

FIG. 4 is a partial end view taken along lines 4-4 of FIG. 2, with portions broken away;

FIG. 5 is a sectional view through one end of a heat transfer roll embodying an alternate arrangement for the spring retainer means and seal;

FIG. 6 is a sectional view through an alternate embodiment of the present invention; and,

FIG. 7 is a greatly enlarged sectional view of one of the spacer elements shown in FIG. 6.

Referring initially to FIGS. I and 2, there is shown one embodiment of a heat transfer roll 10 constructed in accordance with the present invention. Roll 10 includes an inner cylindrical shell 12 enclosed at either end by end plates 14. Shaft members 16 protrude through holes in the end plates 14 and extend axially beyond the ends of the roll to provide means for rotatably mounting the roll. The shaft members are attached to the end plates 14 by any convenient means such as by welding at 18.

The inner shell 12 is provided on its exterior surface with spacer elements in the form of helical baffle members 20 attached thereto by any convenient means such as by spot welding as at 21. The baffle members 20 are inclined at an angle a (see FIG. 2) with respect to a reference line 22 perpendicular to the rotational axis 24 of the roll. The choice of material for the baffle members 20 may vary widely depending on the type of operation contemplated for the roll assembly. However, for reasons to be stated hereafter, it is preferred that the bafile members be fabricated of a relatively stiff thingauged resilient material.

An outer shell 26 surrounds the inner shell 12. The outer shell 26 is radially supported solely by the inclined helical baffle members 20. Baffle members 20 cooperate with the inner and outer shells 12 and 26 to define spiral passageways 28 extending from one end of the roll assembly to the other. The passageways are arranged to accommodate a continuous flow of a heat transfer medium while the roll is in operation. Rotation of the outer shell 26 relative to the inner shell 12 is prevented by any convenient means such as for example, the key 25 shown in FIG. 3. g

A preferred arrangement for circulating the heat transfer medium through spiral passageways 28 will now be described with further reference to FIGS. 2 and 4. Passageways 30a and 30b extend axially through the shaft members 16. For illustrative purposes, passageway 30a is herein designated as the inlet and passageway 30b as the outlet. This arrangement may, however, be reversed depending on how the roll is to be connected to exterior feed and return means (not shown). The inboard end of each passageway 30a and 30b is closed by a small circular plate 32.

The shaft members are each provided with a plurality of radial holes 34 extending from passageways 30a and 30b to chambers 36 formed between end plates 14 and radially extending channel members 38. The channel members 38 are attached as by welding to the shaft members I6 and the end plates 14. Each chamber 36 extends radially from shaft 16 to a ringlike manifold member 40, the latter being attached as by welding as at 42 (see FIG. 3) to the end plate 14 and the channel members 38. The walls of manifold members 40 are suitably apertured as at 44 and 46, the latter apertures being in direct communication with holes 48 extending through end plates 14.

With this construction, any convenient heat transfer medium such as for example water, may enter the roll assembly through passageway 30a. The water will then proceed radially through holes 34 into chambers 36, from whence the water will flow through apertures 44, 46 and 48 into the spiral passageways 28. The water will then proceed along spiral passageways 28 from one end of the roll (the left as viewed in FIG. 1) to the other end at which point the water will proceed in a reverse manner through manifold 40, chambers 36 and apertures 34 to be exhausted through outlet passageway 30b.

. mum-i mu One means for providing a fluidtight seal between the interior and exterior shells at the ends of passageways 28, and for axially retaining the outer shell 26 relative to the inner shell 12, will now be described with particular references to FIGS. 3 and 4. A sealing ring 50 is located in an operative position in contact with the outer face 52 of end plate 14. Sealing ring 50 is provided with two grooves 54a and 54b within which are seated O-rings 56a and 56b. O-ring 56b is forced into groove 54b by being in face-to-face contact with end plate 14, and O- ring 56a is similarly held between the bottom of groove 54a and the interior surface of outer shell 26.

With the sealing ring 50 in place, a retainer assembly generally indicated at 58 is next installed. The retainer assembly includes a pair of ring members 60a and 60b having mating angularly spaced holes 62 suitably dimensioned to receive the ends of coiled springs 64. During installation, the outboard ring 60a is pushed towards end plate 14 to compress springs 64, and is thereafter held in place by means of a snap ring 66 seated in a grove 68 in the interior surface of outer shell 26. The compressive force exerted by springs 64 serves as a means of urging sealing ring 50 against the outboard face 52 of end plate 14, while at the same time yieldingly opposing axial movement in an opposite direction of the outer shell 26 relative to the inner shell 12. By employing this arrangement at one or both ends of the roll, axial expansion and/or contraction of one shell relative to the other is yieldingly accommodated, and at the same time, axial movement of the outer shell relative to the inner shell is yieldingly opposed.

An alternate embodiment of the spring retainer and seal combination is shown in FIG. wherein the inner shell 12a is extended axially as at 70 beyond both end plate 14 and the end of outer shell 26a. The radially extending channel member 38a is attached directly to the end plate 14 and to extension 70 as at 72. The outer shell 26a is provided with a sealing ring 74 attached by means of bolts 76 with a gasket 78 positioned therebetween. A second sealing ring 50a surrounds extension 70 and is located in an operative position in face-toface contact with ring74. Ring 50a is provided with grooves within which are seated O-rings 80a and 80b. Sealing ring 50a is held in place by means of a retainer assembly 58a which includes ring members 82a and 82b suitably drilled at angularly spaced intervals as at 84 to receive the ends of coiled springs 86. Springs 86 are in a state of compression, and the outer ring 820 is axially held in place by means of a snap ring 88 seated in a groove in extension 70.

The chamber 36a defined between channel member 380 and end plate 14 is placed in communication with the annular space 90 between inner and outer shells 12a and 26a by means of a passageway 92 in extension 70. Although not shown in FIG. 5, it is to be understood that as with the arrangement generally described in FIGS. 1-4, there are a plurality of chambers 36a extending radially from the roll shafts and that each chamber is in communication through a plurality of suitably spaced passageways 92 with annular space 90. Similarly, it is to be understood that annular space 90 is suitably divided by inclined baffle members which serve to radially support the outer shell 26a in addition to guiding the flow of a heat transfer medium from one end of the roll to the other.

As previously mentioned, the present invention may also be employed in double-walled roll constructions which do not include means for circulating a heat transfer medium between the inner and outer roll shells. One such construction is illustrated in FIGS. 6 and 7 wherein a roll assembly 94 is shown having inner and outer shells 96 and 98. The inner shell 96 is provided with end plates I00 to which are attached axially extending shaft members 102. The outer shell 98 is again radially supported in relation to the inner shell 96 solely by intermediate spacer elements which in the embodiment shown in FIG. 6 comprise a plurality of annular axially spaced rings 104. The rings 104, which are each fabricated of a relatively thin-gaugedresilient material, such as for example, stainless steel, are again inclined at an angle a" relative to a line 22 perpendicular to the rotational axis of the roll. In this construction, the spacer elements or rings 104 are attached as by spot welding at 106 to the outer shell 98, but it is to be understood that this feature is not essential and that the spacer elements may if desired be attached to the inner shell, as shown in the embodiment previously described and disclosed in FIGS. 1-3.

Axial movement of the outer shell 98 relative to the inner shell 96 is opposed by snap rings I06 seated in grooves in the outer shell 98. The snap rings [06 bear against end plates 100.

Roll assembly 94 is constructed in a manner such as to control deflection of the outer shell 98 caused by radial loading. In the embodiment shown in FIG. 6, this is accomplished by gradually increasing the thickness 1" of the inner shell 96 to a maximum thickness at the roll center. This in turn gradually decreases the radial spacing D" between the inner and outer shells, with the result that the lengths L" of the individual spacer elements 104 are gradually diminished as one approaches the roll center. A decrease in the length "L" of any given element 104 increases its resistance to deflection under a radially applied load P."

Thus it can be seen that deflection of the outer shell 98 can be controlled by varying the ability of individual spacer elements 104 to withstand angular deflection caused by radial loading. In the embodiment shown in FIG. 6, this is accomplished by varying the lengths L" of the individual spacer elements 104. The same result may be obtained by alternately or additionally adjusting other variables such as for example, the modulus of elasticity of the material from which the spacer elements are fabricated, the thickness or gauge of such elements and/or the angle 11" of element inclination. This concept is applicable to roll assemblies employing individual spacer elements 104 of the type shown in FIG. 6, as well as to those assemblies employing continuous spacer elements such as the helical bafile members 20 shown in FIGS. 1-3.

Having thus described several preferred embodiments of industrial rolls constructed in accordance with the present invention, their operation and the advantages to be gained therefrom will now be reviewed briefly. As regards heat transfer rolls of the type generally disclosed in FIGS. 1-4, during operation of the roll, a heat transfer medium is circulated through the spiral passageways 28. A temperature differential will normally exist between the inner and outer roll shells I2 and 26, causing differences in both radial and axial expansion and/or contraction. Differences in radial expansion and/or contraction will be compensated for by deflection of the inclined resilient baffle members 20. The modulus of elasticity, radial length, thickness and angle of inclination of each baffle member is selected so as to control deflection caused by expansion and/or contraction of the inner and outer shells. In this manner, any localized permanent shell deformation which might otherwise take place if thennal stresses were allowed to exceed the elastic limit of the materials employed, will be avoided. Differences in axial expansion and/or contraction are similarly compensated for by the spring-loaded retainer assemblies 58 which yieldingly oppose axial movement of the outer shell relative to the inner shell.

Thus it can be seen that with the above-described construction, the outer shell 26 is in effect allowed to breathe" as temperature differentials are experienced between the inner and outer shells. This avoids any dangerous buildup of local thermal stresses and thus enables the roll to hold its manufactured dimensional tolerances during extended periods of operation.

The manner of providing a seal between the inner and outer shells also embodies important advantages. In the embodiment shown in FIGS. 1-4, the entire sealing function is provided by a simple three-piece assembly made up of one sealing ring 50 and two O-rings 56a and 56b. Once positioned in groove 54b, O-ring 56b is not subjected to any sliding contact when the ring is being installed. Thus there is virtually no chance of the O-ring 56b becoming accidentally dislodged. Because O-ring 56a is clearly visible after the sealing ring 50 has been operatively positioned, it is possible to make a final visual check before installing the retainer assembly 58. Thus a fluidtight seal is easily obtained and positively assured with the foregoing construction. The retainer assemblies 58 and sealing rings 50 may also be readily disassembled by simply removing the snap rings 66. This frees the outer shell 26 for removal when inspection and/or cleaning of the bafile member and inner shell is required. The same advantages are present in the alternate construction shown in FIG. 5.

Finally, it can now be appreciated by those skilled in the art that by radially supporting the outer roll shell solely by the use of resilient inclined spacer elements, deflection of the outer shell can be controlled to a considerable degree. This can be accomplished by adjusting a number of variables such as for example the modulus of elasticity, radial length, thickness and/or angle of inclination of the spacer elements.

It is my intention to cover all changes and modifications of the embodiment herein chosen for purposes of disclosure which do not depart from the spirit and scope of the invention.

1 claim:

1. An industrial roll assembly comprising in combination: inner and outer concentrically arranged cylindrical shells, the said shells being radially spaced to define an annular chamber therebetween; at least one resilient spacer element in said chamber, the said outer shell being radially supported solely by said spacer element, said spacer element being inclined relative to a line perpendicular to the rotational axis of the roll, the inclination and resiliency of said spacer element being such as to permit relative radial expansion and contraction of one shell relative to the other shell; means for preventing rotation of said outer shell relative to said inner shell; and, retainer means for closing the ends of said chamber and for opposing axial movement of one shell relative to the other shell.

2. The apparatus as claimed in claim 1 wherein said spacer element is secured to one of said cylindrical shells.

3. The apparatus as claimed in claim 1 wherein said spacer element is comprised of at least one helical baffle member, the said baffle member cooperating with said inner and outer shells to subdivide said chamber into a plurality of spiral passageways extending from one end to the other of said roll assembly.

4. The apparatus as claimed in claim 3 further characterized by shaft means at either end of said inner shell; inlet and outlet passageways in said shaft means; and, radially extending conduit means connecting said inlet and outlet passageways to said spiral passageways.

5. A heat transfer roll comprising in combination: inner and outer concentrically arranged radially spaced cylindrical shells; shaft means at either end of said inner shell; helical baffle means positioned between said inner and outer shells, said bafi'le means being resilient and inclined relative to a line perpendicular to the rotational axis of said roll, said outer shell being radially supported solely by said bafi'le means, the said baffle means cooperating with said inner and outer shells to define spiral passageways extending from one end to the other of said roll, the inclination and resiliency of said baffle means being such as to permit relative radial expansion and contraction of one shell relative to the other shell; inlet and outlet passageways in said shaft means; retainer means for closing the ends of said spiral passageways and for yieldingly opposing axial movement of said outer shell relative to said inner shell; and, conduit means connecting said inlet and outlet passageways to the opposite ends respectively of said spiral passageways.

6. A heat transfer roll comprising in combination: A cylindrical inner shell; plate members closing the ends of said shell, the peripheral edges of said plate members extending radially from said inner shell; shaft means fixed to and extending axially from said plate members; helical baffle means fixed to and extending radially from said inner shell, the said baffle means being resilient and inclined relative to a line perpendicular to the rotational axis of said roll, the inclination and resiliency of said baffle means being such as to permit relative radial expansion and contraction of one shell relative to the other shell; a cylindrical outer shell separable from and radially supported solely by said baffle means in a position surrounding said inner shell, the said baffle means cooperating with said inner and outer shells to define spiral passageways extending from one end of said roll to the other; retaining means cooperating with the peripheral edges of said plate members to close the ends of said spiral passageways and to yieldingly oppose axial'movement of said outer shell relative to said inner shell; inlet and outlet passageways in said shaft means; and, conduit means cooperating with said plate members for connecting said inlet and outlet passageways to the opposite ends respectively of said spiral passageways.

ll 1k uurna All-l 

1. An industrial roll assembly comprising in combination: inner and outer concentrically arranged cylindrical shells, the said shells being radially spaced to define an annular chamber therebetween; at least one resilient spacer element in said chamber, the said outer shell being radially supported solely by said spacer element, said spacer element being inclined relative to a line perpendicular to the rotational axis of the roll, the inclination and resiliency of said spacer element being such as to permit relative radial expansion and contraction of one shell relative to the other shell; means for preventing rotation of said outer shell relative to said inner shell; and, retainer means for closing the ends of said chamber and for opposing axial movement of one shell relative to the other shell.
 2. The apparatus as claimed in claim 1 wherein said spacer element is secured to one of said cylindrical shells.
 3. The apparatus as claimed in claim 1 wherein said spacer element is comprised of at least one helical baffle member, the said baffle member cooperating with said inner and outer shells to subdivide said chamber into a plurality of spiral passageways extending from one end to the other of said roll assembly.
 4. The apparatus as claimed in claim 3 further characterized by shaft means at either end of said inner shell; inlet and outlet passageways in said shaft means; and, radially extending conduit means connecting said inlet and outlet passageways to said spiral passageways.
 5. A heat transfer roll comprising in combination: inner and outer concentrically arranged radially spaced cylindrical shells; shaft means at either end of said inner shell; helical baffle means positioned between said inner and outer shells, said baffle means being resilient and inclined relative to a line perpendicular to the rotational axis of said roll, said outer shell being radially supported solely by said baffle means, the said baffle means cooperating with said inner and outer shells to define spiral passageways extending from one end to the other of said roll, the inclination and resiliency of said baffle means being such as to permit relative radial expansion and contraction of one shell relative to the other shell; inlet and outlet passageways in said shaft means; retainer means for closing the ends of said spiral passageways and for yieldingly opposing axial movement of said outer shell relative to said inner shell; and, conduit means connecting said inlet and outlet passageways to the opposite ends respectively of said spiral passageways.
 6. A heat transfer roll comprising in combination: a cylindrical inner shell; plate members closing the ends of said shell, the peripheral edges of said plate members extending radially from said inner shell; shaft means fixed to and extending axially from said plate members; helical baffle means fixed to and extending radially from said inner shell, the said baffle means being resilient and inclined relative to a line perpendicular to the rotational axis of said roll, the inclination and resiliency of said baffle means being such as to permit relative radial expansion and contraction of one shell relative to the other shell; a cylindrical outer shell separable from and radially supported solely by said baffle means in a position surrounding said inner shell, the said baffle means cooperating with said inner and outer shells to define spiral passageways extending from one end of said roll to the other; retaining means cooperating with the peripheral edges of said plate members to close the ends of said spiral passageways and to yieldingly oppose axial movement of said outer shell relative to said inner shell; inlet and outlet passageways in said shaft means; and, conduit means cooperating with said plate members for connecting said inlet and outlet passageways to the opposite ends respectively of said spiral passageways. 